Board Thread:Off Topic/@comment-31658174-20170620034623/@comment-30155146-20170727043504

Because you can only mega one mon. Some pokemon actually require their mega stone to be effective,such as char, so you essentially hold them back after choosing one mon. In addition, it's a waste of an item slot. there is no advantage of having multiple mega stones as an adaptive strategy unless the mega changes type weaknesses so much that the essential teams structUre changes. Use other items for other slots, such as life orb.

Spikes is good for a PROTEAN gren due to electric defensive coverage, but other than that it dilutes gren/a-grens role as a sweeper/wallbreaker.